1. Field of the Invention
The present invention relates to a light source device, a light source unit including the light source device, and a projector including the light source unit and adapted to project an image based on a video signal.
2. Description of the Related Art
Currently, data projectors are used in many cases which function as image projection units for projecting a screen of a personal computer, a video image, and furthermore, an image based on image data stored in a memory card on to a screen. In recent years, the miniaturization of projectors have been in progress and in association with this trend, progress in miniaturization of light source devices has also been made so that light source devices can be accommodated in interiors of housings of those miniaturized projectors. Consequently, in order to provide a projection image of high luminance using such a miniaturized light source device, it is necessary to make efficient use of emerging light from the miniaturized light source device or reduce wasteful diffused light in light emitted from the light source device. For example, the Japanese Unexamined Patent Publication No. 2002-303818 proposes a light source device in which a conical mirror is disposed on a circumferential edge of a light source in which an inner surface which becomes progressively wider towards a light emitting end is made to constitute a reflection surface. According to the proposal of this patent document, since light emitted from the light source is reflected on the reflection surface of the conical mirror to thereby be made substantially parallel to the optical axis, the utilization efficiency of light incident on an optical system positioned to the rear of the light source device is increased.
As has been described above, the miniaturization of light source devices has been in progress in parallel with the recent trend of miniaturization of projectors. Consequently, in order to enable the projection of images of high luminance, it is necessary to increase the utilization of light emitted from the light source unit.